The present invention relates to a reciprocating motion electric shaver provided with outer blades and inner blades.
The reciprocating motion electric shaver cuts the beard with the outer blades provided with ports introducing the beard and inner blades provided with plural inner blade main pieces that move with a reciprocating motion rubbing the inner face of the outer blade. As to the shape of the outer blades and inner blades of the reciprocating motion electric shaver, the type with the inner blade main pieces formed like a circular arc and outer blade bent like an arch fitting the arc of the inner blade, is widely known.
The reciprocating motion electric shaver with an outer blade shaped with a square cross section, is also known. The outer blades or the inner blades with a square cross section are much easier to manufacture compared with the outer blades bent like an arch, and it is also possible to make them narrower.
Therefore, with the reciprocating motion electric shaver that is provided with more than one outer blade like 2 rows of blades or 3 rows of blades, it is possible to make the head part more compact by making the outer blades square.
The reciprocating motion electric shaver of the prior art with square shaped outer blades or inner blades is shown in FIG. 1 to FIG. 3. In these Figures, the outer blade is numbered 26 and the inner blade 27. The outer blade 26 is formed square, the upper face part 28 is formed horizontal, from each extremity of the upper face part 28, the lateral face part 29 extends down vertically. Each extremity 29 of the upper face part 28 joined to the lateral face part 29 is shaped like an arch to provide a comfortable touch with the skin. Then, from the upper face part 28 to the upper part of each lateral face part 29 slit ports are provided to introduce the beard in. Then the outer blades 26 are fixed to the head part, of the body of the reciprocating motion electric shaver.
The inner blade 27 is shaped square. Furthermore, on the inner blade, the inner blade base 30 made of stainless steel or other, has a square bend and in the square bent part several parallel slits 31 are formed. As a result, owing to the thin parts located between the slits 31, the inner blade 27 is shaped with several inner blade main pieces 32. Each inner blade main piece 32 is composed of the base part 33 connected to the inner blade base 30 and of the beard cutting blade portion 34 connecting each opposing part of each extremity of the base part 33. Compared with the base part 33 that is formed vertically, the beard cutting blade portion 34 is formed perpendicularly horizontal. The upper face of the beard cutting blade portion 34 is formed by the sharply grinded edge 35. The inner blade 27 is located at the position where it contacts and rubs the inner face of the outer blade 26 and it is connected to the motor built-in in the reciprocating motion electric shaver to drive the reciprocating motion.
The length of upper face part 28 of the outer blade 26 is designed to be a little longer than the length of the beard cutting blade portion 34 of the inner blade main piece 32. Therefore, there is a gap between the lateral face part 29 of the outer blade 26 and the opposing base part 33 of the inner blade main piece 32. Through the existence of this gap, the beard is introduced more easily through the lateral face.
The beard that has been introduced by the slit port 4 of the outer blade 26, is cut by the edge 35 of the inner blade main piece 32. The edge 35 formed by the beard cutting blade portion 34 of inner blade main piece 32 and because it is formed by the span A of the FIG. 3, will not cut the beard if the beard that has been introduced, does not reach this span A. Nevertheless, in the case of a vicious beard like a long beard, it is very often introduced from the lateral face part 29 of the outer blade 26, and in this case because of the existence of the inner blade base 30, the space where the beard is introduced, is limited. For example, as shown in FIG. 3. the beard that has been introduced from the left side of the lateral face part 29 of the outer blade 26, is obstructed by the inner blade base 30 and cannot reach the span A. As a result, a vicious beard like a long beard cannot be shaved and unshaved zones will be left.
Furthermore, the outer blade of the hereabove construction has also the drawback that it is not able to pull the totality of the vicious beard into the slit ports. It is possible to improve the introduction of the vicious beard of the outer blade by making the slit ports wider. But, when making the slit ports wider. the, consequence is that the skin can more easily be damaged. The skin is pressed into the wide slit ports, and cut by the inner blade that rubs the inner face. To be able to protect the skin, the width of the slit ports is made narrower, the introduction of the vicious beard is proportionally worthless. Being able to cut the vicious beard precisely with the outer blades and not damage the skin are two opposite specific characteristics.
Because the present invention has been developed to solve the above drawbacks, the first purpose of the present invention, reducing the damage of the skin, is to supply an electric shaver that can precisely cut a vicious beard.
By the way, square shaped outer blades can be mass produced at low cost, by embossing a metallic sheet. By this method, after having opened the slit ports by embossing the flat metallic sheet, the latter is square bent. By this method it is possible to produce a large quantity of outer blades with a high efficiency but it is not possible to produce an ideal shape that cuts very well. It is possible to improve the cutting of the outer blade by sharpening the angle of the edge formed by the opposite face of the slit ports and the outer blades of the inner face. But in the manufacturing process by embossing, it is not possible to manufacture an edge with a sharper angle. Furthermore, to improve the cutting of the slit port and the inner blade it is necessary to position the inner blade a little slant compared with the slit ports. With this structure, the inner blade and the slit ports, like cutting the beard with scissors, approaching and crossing together, precisely cut the beard. But to be able to realize this structure, it is necessary to make the slit ports and the inner blade slant, and the manufacturing is then more difficult.
The second purpose of the present invention, is to solve this drawback, that is to say, to propose a manufacturing method of the outer blades of an electric shaver, that allows a low price, and simple and easy large quantity manufacturing of sharp outer blades.
Furthermore, the inner blade 27 shown in FIG. 1 and FIG. 2, is formed by folding one sheet of stainless steel at 180 degrees to obtain a horizontal "U" shape. Therefore, the inner blade base 30 is positioned opposite with a fixed interval. For this reason, because the width of the inner blade 27 gets wider only where there is this interval, this hinders the miniaturization.
Furthermore, because the process of folding the inner blade base 30 is necessary, the production cost increases. Then, to allow the folding, because it is not possible to augment the thickness of the inner blade base 30, the drawback is that a large mechanical resistance cannot be reached.
The third purpose of the present invention is to supply an electric shaver provided with an inner blade with a high mechanical resistance, miniaturized and that can be manufactured extremely easily.
The above and further objects and features of the invention will more fully be apparent from the following description with accompanying drawings.